捕获错误并暂停程序的正确方法是什么？

Question

My intent is to break and return an error to the user upon a failed validation (using dry-validation).

Within a service object, I have:

def perform
  validate_coupon
  create_stripe_coupon
rescue ActiveRecord::RecordInvalid, ::Stripe::StripeError => exception
  puts "[STRIPE] Problem: #{exception.message}"
  OpenStruct.new(success?: false, coupon: coupon, error: exception.message)
else
  OpenStruct.new(success?: true, coupon: coupon)
end

def validate_coupon
  validate_coupon_object
rescue CouponError => exception
  puts "[CouponError] #{exception.message}"
  OpenStruct.new(success?: false, coupon: coupon, error: exception.message)
else
  OpenStruct.new(success?: true, coupon: coupon)
end

def create_stripe_coupon
  @coupon = ::Stripe::Coupon.create(
    :name => @coupon.name,
    :duration => @coupon.duration,
    :percent_off => @coupon.percent_off,
    :max_redemptions => @coupon.max_redemptions
    )
  save_coupon_object
end

I raise a custom error here in validate_coupon.rb:

module PaymentServices
  module Stripe
    module Coupon
      module ValidateCoupon

        def schema
          Dry::Validation.Schema do
            required(:name) { str? }
            required(:duration) { str? }
            required(:percent_off) { gt?(0) & lt?(101) }
            required(:max_redemptions) { int? & gt?(0) }
          end
        end

        def validate_coupon_object
          result = schema.call(
            name: @coupon.name,
            duration: @coupon.duration,
            percent_off: @coupon.percent_off,
            max_redemptions: @coupon.max_redemptions
            )
          raise CouponError.new(result) if result.failure?
        end

      end
    end
  end
end

When the validation fails, the program throws the error but continues on and executes create_stripe_coupon .

My desire is to break when the error is thrown within validate_coupon , thus stopping create_stripe_coupon from running.

What is the best approach for this?

Answer 1

The problem is that the exception is rescued in validate_coupon method:

def validate_coupon
  validate_coupon_object
rescue CouponError => exception
  puts "[CouponError] #{exception.message}"
  OpenStruct.new(success?: false, coupon: coupon, error: exception.message)
else
  OpenStruct.new(success?: true, coupon: coupon)
end

And the perform method knows nothing about the failure that happened in validate_coupon method:

def perform
  validate_coupon
  create_stripe_coupon
rescue ActiveRecord::RecordInvalid, ::Stripe::StripeError => exception
  puts "[STRIPE] Problem: #{exception.message}"
  OpenStruct.new(success?: false, coupon: coupon, error: exception.message)
else
  OpenStruct.new(success?: true, coupon: coupon)
end

In order to fix it, you need something like:

def perform
  result = validate_coupon
  create_stripe_coupon if result.success?
rescue ActiveRecord::RecordInvalid, ::Stripe::StripeError => exception
  puts "[STRIPE] Problem: #{exception.message}"
  OpenStruct.new(success?: false, coupon: coupon, error: exception.message)
else
  OpenStruct.new(success?: true, coupon: coupon)
end

Or

def validate_coupon
  validate_coupon_object
rescue CouponError => exception
  puts "[CouponError] #{exception.message}"
  raise ActiveRecord::RecordInvalid
end